Providing user interface (UI) elements having scrollable content in virtual machine sessions at reduced latency and related methods

ABSTRACT

A computing system includes a virtualization server that runs virtual machine sessions and provides a hosted application with user interface (UI) elements having scrollable content. A client computing device accesses the hosted application during one of the virtual machine sessions and receives the scrollable content. The client computing device displays at least a portion of the scrollable content as local virtual UI elements, applies user input to scroll the portion of the scrollable content in focus, caches scrollable content that is positioned adjacent the portion of the scrollable content being scrolled that is not in focus, and generates a local virtual UI element graphics overlay that includes at least a portion of the cached scrollable content for display corresponding to a predicted response to the user input.

PRIORITY APPLICATION(S)

This is a continuation application based upon U.S. patent applicationSer. No. 16/365,753 filed Mar. 27, 2019, the disclosure which is herebyincorporated by reference in its entirety.

BACKGROUND

Traditionally, personal computers include combinations of operatingsystems, applications, and user settings, which are each managedindividually by owners or administrators on an ongoing basis. However,many organizations are now using desktop virtualization to provide amore flexible option to address the varying needs of their users.

In desktop virtualization, a user's computing environment (e.g.,operating system, applications, and/or user settings) may be separatedfrom the user's physical computing device (e.g., smartphone, laptop,desktop computer). Using client-server technology, a “virtualizeddesktop” may be stored in and administered by a remote server, ratherthan in the local storage of the client computing device.

Desktop virtualization systems may be implemented using a singlevirtualization server or a combination of servers interconnected as aserver grid. For example, a cloud computing environment, or cloudsystem, may include a pool of computing resources (e.g., desktopvirtualization servers), storage disks, networking hardware, and otherphysical resources that may be used to provision virtual desktops, alongwith additional computing devices to provide management and customerportals for the cloud system.

As more workloads are migrated into these cloud systems and data centersare consolidated across continents, however, the network conditionsbetween the workloads and the endpoints at the client computing devicesbecome more challenging and are characterized with much higher latencyand packet loss. This creates a poor user experience (UX) since a timelag appears to the user, especially when navigating user interface (UI)elements in response to different user input such as scrolling ortabbing.

SUMMARY

A computing system includes a virtualization server configured to runvirtual machine sessions and provide a hosted application during thevirtual machine sessions. The hosted application includes user interface(UI) elements having scrollable content. At least one client computingdevice is configured to access the hosted application during one of thevirtual machine sessions with the virtualization server so as to receivethe scrollable content. The at least one client computing device isconfigured to display at least a portion of the scrollable content aslocal virtual UI elements, apply user input to scroll the portion of thescrollable content in focus, cache scrollable content that is positionedadjacent the portion of the scrollable content being scrolled that isnot in focus, generate a local virtual UI element graphics overlay thatincludes at least a portion of the cached scrollable content for displaycorresponding to a predicted response to the user input, and send theuser input to the virtualization server.

The virtualization server is configured to apply the received user inputto the hosted application, generate an updated UI element graphics thatincludes at least the portion of the cached scrollable contentcorresponding to an actual response to the user input, and send theupdated UI element graphics to the at least one client computing device.

The at least one client computing device is configured to replace atleast a portion of the local virtual UI element graphics overlay withthe received updated UI element graphics, which may be based on anestimated latency between the virtualization server and the at least oneclient computing device. The estimated latency may be based on at leastone of an average, a median and a standard deviation of latenciesbetween the virtualization server and the at least one client computingdevice.

The replacement of at least a portion of the local virtual UI elementgraphics overlay with the received updated UI element graphics may beperformed by hiding said at least a portion of the local virtual UIelement graphics overlay and unveiling the said received updated UIelement graphics underneath the said at least a portion of the localvirtual UI element graphics overlay. Metadata may be associated with thescrollable content, which may include text, and also may include atleast one of grid item, table item, spreadsheet item, list item, anddata item. The metadata may also include encrypted text and may includeat least one of UI automation properties and events retrieved from thehosted application.

The scrollable content may include at least one of vertically scrollablecontent and horizontally scrollable content that includes a scrollpattern and at least one of a text pattern, grid pattern, table pattern,spreadsheet pattern, and a list pattern. The local virtual UI elementgraphics overlay may be deleted based on one or more of replacing thesaid local virtual UI element graphics overlay with the received updatedUI element graphics, hosted application process terminating, hostedapplication window closing, hosted application UI element getting out offocus, hosted application UI element becoming hidden, hosted applicationUI element being deleted, heuristics specific to receiving the hostedapplication UI element, and policies associated with displaying thereceived hosted application UI element.

Another aspect is directed to a method for operating virtual machinesessions provided by a virtualization server in communication with atleast one client computing device to provide a hosted application thatincludes user interface (UI) elements having scrollable content. Themethod includes accessing the hosted application from at least oneclient computing device during one of the virtual machines sessions forreceiving the UI elements having scrollable content, wherein the clientcomputing device is operable for displaying at least a portion of thescrollable content as local virtual UI elements, applying user input toscroll the portion of the scrollable content in focus, cachingscrollable content that is positioned adjacent the portion of thescrollable content being scrolled that is not in focus, generating alocal virtual UI element graphics overlay that includes at least aportion of the cached scrollable content for display corresponding to apredicted response to the user input, and sending the user input to thevirtualization server.

Yet another aspect is directed to a non-transitory computer readablemedium for operating virtual machine sessions provided by avirtualization server in communication with at least one clientcomputing device and providing a hosted application that includes userinterface (UI) elements having scrollable content that are displayed atthe client computing device. The non-transitory computer readable mediumhas a plurality of computer executable instructions for causing theclient computing device to perform steps as described above.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a network environment of computing devicesin which various aspects of the disclosure may be implemented.

FIG. 2 is a block diagram of a computing device useful for practicing anembodiment of the client machines or the remote machines illustrated inFIG. 1 .

FIG. 3 is block diagram of a computing system for reduced latencynavigation of UI elements in a first aspect that includes a clientcomputing device that displays user interface (UI) elements as apredicted response to user input and a virtualization server thatprovides updated UI element graphics for the actual response to userinput.

FIG. 4 is a flowchart illustrating a method for operating the clientcomputing device illustrated in FIG. 3 .

FIG. 5 is a block diagram of the computing system of FIG. 3 in a secondaspect that includes a client computing device that displays UI elementshaving scrollable content and the virtualization server that providesupdated UI elements.

FIG. 6 is a flowchart illustrating a method for operating the clientcomputing device illustrated in FIG. 5 .

FIG. 7 is a flowchart illustrating a method for operating thevirtualization server illustrated in FIG. 5 .

FIG. 8 is a block diagram of the computing system of FIG. 3 in a thirdaspect that includes a client computing device that displays UI elementshaving an ordered hierarchy of graphical control elements and thevirtualization server that provides updated UI element graphics.

FIG. 9 is a flowchart illustrating a method for operating the clientcomputing device illustrated in FIG. 8 .

FIG. 10 is a flowchart illustrating a method for operating thevirtualization server illustrated in FIG. 8 .

FIG. 11 is a chart showing examples of the round trip time (RTT) fordifferent points of presence (POP) and gateways resulting in highlatency experienced by users at client computing devices.

FIG. 12 is a sequence diagram showing the data flow for reduced latencynavigation of UI elements common to the computing systems of FIGS. 3, 5,and 8 .

FIG. 13 is an example screenshot of retrieving text and font propertiesunder the cursor in a Notepad program when operating the computingsystem for reduced latency navigation of UI elements.

FIG. 14 is another example screenshot similar to that of FIG. 13 , butwith an example Microsoft Word program.

FIG. 15 is yet another example screenshot similar that of FIGS. 13 and14 , but with an example Microsoft Excel program.

FIG. 16 is a graphical representation of cached scrollable content andgraphics at Time 1 and Time 2 in a document when operating the computingsystem for reduced latency navigation of UI elements.

FIG. 17 is an example of a screenshot in an example scrolling andretrieving of text in a document of a Microsoft Word program whenoperating the computing system for reduced latency navigation of UIelements.

FIG. 18 is an example of a fragmentary drawing of a screenshot in anexample window/container scrolling using cached content as start menuoptions when operating the computing system for reduced latencynavigation of UI elements.

FIG. 19 is a block diagram of the client computing device and showingdiagrammatically a next graphical control element as a tab in an orderedhierarchy for reduced latency navigation of UI elements.

FIG. 20 is a diagram of text having an embedded table and image as anexample for navigating in a table for reduced latency navigation of UIelements.

FIG. 21 is a graphical content view of the text container of thedocument shown in FIG. 20 .

FIG. 22 is an example screenshot of a combo box in a webpage that uses apicker control that can be cached and optimized for reduced latencynavigation of UI elements.

FIG. 23 shows the combo box of FIG. 22 with a combo box selection in thewebpage.

DETAILED DESCRIPTION

The present description is made with reference to the accompanyingdrawings, in which exemplary embodiments are shown. However, manydifferent embodiments may be used, and thus the description should notbe construed as limited to the particular embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete. Like numbers refer to like elements throughout.

As will be discussed in greater detail below, the computing system hasthree different aspects and provides for reduced latency User Interface(UI) element navigation in virtual applications. Because the latencyreduction in effect is substantial, it may appear to the user as a zerolatency navigation of UI elements when tabbing, scrolling and performingother similar functions. These three major aspects are generallydescribed, followed by a more detailed analysis.

In a first aspect, a hosted application on a virtualization serverincludes user interface (UI) elements. A client computing deviceaccesses the hosted application during a virtual machine session,receives the UI elements, and displays the UI elements as local hiddenvirtual UI elements. User input is applied to a local virtual UI elementin focus and a local visible virtual UI element graphics overlay isgenerated corresponding to a predicted response to user input. Userinput is sent to the virtualization server, which in turn, generatesupdated UI element graphics corresponding to an actual response to theuser input. Those updated UI element graphics are sent to the clientcomputing device, which replaces at least a portion of the local visiblevirtual UI element graphics overlay corresponding to the predictedresponse.

In a second aspect, the hosted application may include UI elementshaving scrollable content. The client computing device may not onlydisplay at least a portion of the scrollable content but may also createcorresponding local hidden virtual UI elements. The client computingdevice may also apply user input to scroll a portion of the scrollablecontent in focus and cache scrollable content that is positionedadjacent to the portion of the scrollable content being scrolled that isnot in focus and generate the local visible virtual UI element graphicsoverlay that includes at least a portion of the cached scrollablecontent for display corresponding to a predicted response to the userinput. The virtualization server may generate updated UI elementgraphics that include at least a portion of the cached scrollablecontent corresponding to an actual response to the user input and sendthe updated UI element graphics to the client computing device.

In a third aspect, the UI elements are in an ordered hierarchy ofgraphical control elements when sequenced therethrough such as when auser selects a tab, button, menu, jump list, toggle, and picker controlvia an input device. A UI element in focus may be highlighted, e.g., asa rectangle. A UI element may include data being cached by the at leastone client computing device. The caching by the at least one clientcomputing device may be performed when the corresponding graphicalcontrol element is in focus. In other embodiments the caching by the atleast one client computing device may be performed even when thecorresponding graphical control element is not in focus.

In the description that follows, the first aspect of the computingsystem is shown generally at FIGS. 3 and 4 , the second aspect of thecomputing system directed to scrolling is shown generally at FIGS. 5-7 ,and the third aspect of the computing system directed to the orderedhierarchy of graphical control elements is shown generally at FIGS. 8-10. These descriptions are followed by a more detailed description of thecomputing systems and a detailed sequence diagram of the data flowcommon to the computing systems, specific screenshots as non-limitingexamples of what types of programs can have the reduced, i.e., zerolatency navigation of UI elements, and diagrams of specific examples.

As will be appreciated by one of skill in the art upon reading thefollowing disclosure, various aspects described herein may be embodiedas a device, a method or a computer program product (e.g., anon-transitory computer-readable medium having computer executableinstruction for performing the noted operations or steps). Accordingly,those aspects may take the form of an entirely hardware embodiment, anentirely software embodiment or an embodiment combining software andhardware aspects.

Furthermore, such aspects may take the form of a computer programproduct stored by one or more computer-readable storage media havingcomputer-readable program code, or instructions, embodied in or on thestorage media. Any suitable computer readable storage media may beutilized, including hard disks, CD-ROMs, optical storage devices,magnetic storage devices, and/or any combination thereof.

Referring initially to FIG. 1 , a non-limiting network environment 101in which various aspects of the disclosure may be implemented includesone or more client machines 102A-102N, one or more remote machines106A-106N, one or more networks 104, 104′, and one or more appliances108 installed within the computing environment 101. The client machines102A-102N communicate with the remote machines 106A-106N via thenetworks 104, 104′.

In some embodiments, the client machines 102A-102N communicate with theremote machines 106A-106N via an intermediary appliance 108. Theillustrated appliance 108 is positioned between the networks 104, 104′and may be referred to as a network interface or gateway. In someembodiments, the appliance 108 may operate as an application deliverycontroller (ADC) to provide clients with access to business applicationsand other data deployed in a datacenter, the cloud, or delivered asSoftware as a Service (SaaS) across a range of client devices, and/orprovide other functionality such as load balancing, etc. In someembodiments, multiple appliances 108 may be used, and the appliance(s)108 may be deployed as part of the network 104 and/or 104′.

The client machines 102A-102N may be generally referred to as clientmachines 102, local machines 102, clients 102, client nodes 102, clientcomputers 102, client devices 102, computing devices 102, endpoints 102,or endpoint nodes 102. The remote machines 106A-106N may be generallyreferred to as servers 106 or a server farm 106. In some embodiments, aclient device 102 may have the capacity to function as both a clientnode seeking access to resources provided by a server 106 and as aserver 106 providing access to hosted resources for other client devices102A-102N. The networks 104, 104′ may be generally referred to as anetwork 104. The networks 104 may be configured in any combination ofwired and wireless networks.

A server 106 may be any server type such as, for example: a file server;an application server; a web server; a proxy server; an appliance; anetwork appliance; a gateway; an application gateway; a gateway server;a virtualization server; a deployment server; a Secure Sockets LayerVirtual Private Network (SSL VPN) server; a firewall; a web server; aserver executing an active directory; or a server executing anapplication acceleration program that provides firewall functionality,application functionality, or load balancing functionality.

A server 106 may execute, operate or otherwise provide an applicationthat may be any one of the following: software; a program; executableinstructions; a virtual machine; a hypervisor; a web browser; aweb-based client; a client-server application; a thin-client computingclient; an ActiveX control; a Java applet; software related to voiceover internet protocol (VoIP) communications like a soft IP telephone;an application for streaming video and/or audio; an application forfacilitating real-time-data communications; a HTTP client; a FTP client;an Oscar client; a Telnet client; or any other set of executableinstructions.

In some embodiments, a server 106 may execute a remote presentationclient or other client or program that uses a thin-client or aremote-display protocol to capture display output generated by anapplication executing on a server 106 and transmits the applicationdisplay output to a client device 102.

In yet other embodiments, a server 106 may execute a virtual machineproviding, to a user of a client device 102, access to a computingenvironment. The client device 102 may be a virtual machine. The virtualmachine may be managed by, for example, a hypervisor, a virtual machinemanager (VMM), or any other hardware virtualization technique within theserver 106.

In some embodiments, the network 104 may be: a local-area network (LAN);a metropolitan area network (MAN); a wide area network (WAN); a primarypublic network 104; and a primary private network 104. Additionalembodiments may include a network 104 of mobile telephone networks thatuse various protocols to communicate among mobile devices. For shortrange communications within a WLAN, the protocols may include 802.11,Bluetooth, and Near Field Communication (NFC).

FIG. 2 depicts a block diagram of a computing device 100 useful forpracticing an embodiment of client devices 102 or servers 106. Thecomputing device 100 includes one or more processors 103, volatilememory 122 (e.g., random access memory (RAM)), non-volatile memory 128,user interface (UI) 123, one or more communications interfaces 118, anda communications bus 150.

The non-volatile memory 128 may include: one or more hard disk drives(HDDs) or other magnetic or optical storage media; one or more solidstate drives (SSDs), such as a flash drive or other solid state storagemedia; one or more hybrid magnetic and solid state drives; and/or one ormore virtual storage volumes, such as a cloud storage, or a combinationof such physical storage volumes and virtual storage volumes or arraysthereof.

The user interface 123 may include a graphical user interface (GUI) 124(e.g., a touchscreen, a display, etc.) and one or more input/output(I/O) devices 126 (e.g., a mouse, a keyboard, a microphone, one or morespeakers, one or more cameras, one or more biometric scanners, one ormore environmental sensors, and one or more accelerometers, etc.).

The non-volatile memory 128 stores an operating system 115, one or moreapplications 116, and data 117 such that, for example, computerinstructions of the operating system 115 and/or the applications 116 areexecuted by processor(s) 103 out of the volatile memory 122. In someembodiments, the volatile memory 122 may include one or more types ofRAM and/or a cache memory that may offer a faster response time than amain memory. Data may be entered using an input device of the GUI 124 orreceived from the I/O device(s) 126. Various elements of the computer100 may communicate via the communications bus 150.

The illustrated computing device 100 is shown merely as an exampleclient device or server, and may be implemented by any computing orprocessing environment with any type of machine or set of machines thatmay have suitable hardware and/or software capable of operating asdescribed herein.

The processor(s) 103 may be implemented by one or more programmableprocessors to execute one or more executable instructions, such as acomputer program, to perform the functions of the system. As usedherein, the term “processor” describes circuitry that performs afunction, an operation, or a sequence of operations. The function,operation, or sequence of operations may be hard coded into thecircuitry or soft coded by way of instructions held in a memory deviceand executed by the circuitry. A processor may perform the function,operation, or sequence of operations using digital values and/or usinganalog signals.

In some embodiments, the processor can be embodied in one or moreapplication specific integrated circuits (ASICs), microprocessors,digital signal processors (DSPs), graphics processing units (GPUs),microcontrollers, field programmable gate arrays (FPGAs), programmablelogic arrays (PLAs), multi-core processors, or general-purpose computerswith associated memory.

The processor may be analog, digital or mixed-signal. In someembodiments, the processor may be one or more physical processors, orone or more virtual (e.g., remotely located or cloud) processors. Aprocessor including multiple processor cores and/or multiple processorsmay provide functionality for parallel, simultaneous execution ofinstructions or for parallel, simultaneous execution of one instructionon more than one piece of data.

The communications interfaces 118 may include one or more interfaces toenable the computing device 100 to access a computer network such as aLocal Area Network (LAN), a Wide Area Network (WAN), a Personal AreaNetwork (PAN), or the Internet through a variety of wired and/orwireless connections, including cellular connections.

In described embodiments, the computing device 100 may execute anapplication on behalf of a user of a client device. For example, thecomputing device 100 may execute one or more virtual machines managed bya hypervisor. Each virtual machine may provide an execution sessionwithin which applications execute on behalf of a user or a clientdevice, such as a hosted desktop session. The computing device 100 mayalso execute a terminal services session to provide a hosted desktopenvironment. The computing device 100 may provide access to a remotecomputing environment including one or more applications, one or moredesktop applications, and one or more desktop sessions in which one ormore applications may execute.

Additional descriptions of a computing device 100 configured as a clientdevice 102 or as a server 106, or as an appliance intermediary to aclient device 102 and a server 106, and operations thereof, may be foundin U.S. Pat. Nos. 9,176,744 and 9,538,345, which are incorporated hereinby reference in their entirety. The '744 and '345 patents are bothassigned to the current assignee of the present disclosure.

There now follows a description of the computing system that mayincorporate the computing device 100, client device 102, server 106, andother components such that a user at a client device 102 may navigate UIelements and visually to the user, it will appear there is zero latencynavigation of the UI elements since the latency has been substantiallyreduced by displaying the predicted and later actual response to userinput.

The computing system, in accordance with the first, second and thirdaspects, provides a reduced and what appears to the user to be a zerolatency navigation of UI elements in virtual applications. The computingsystem is an improvement over traditional local text echo for typing,such as disclosed in commonly assigned U.S. Pat. No. 6,538,667, thedisclosure which is hereby incorporated by reference in its entirety.The computing system provides local and what appears to be instant orzero latency UI element navigation for actions such as tabbing,scrolling, navigating in grid controls, opening/closing and navigationand selecting from picker controls, menus, jump lists, changing stateand toggle controls, and similar functions, using almost any user inputat a keyboard, mouse, touch pad, pen, or similar input device.

The approach of local text echo for typing as disclosed in theincorporated by reference '667 patent is based on input position andfont information from a virtual application. That system as disclosed inthe '667 patent is currently used in the Receiver and XenAppapplications manufactured by Citrix Systems, Inc. under conditions ofhigh latency. The improvements implemented by the computing systemhaving the reduced, i.e., zero latency navigation of UI elements may beimplemented with the local text echo based on the applicationprogramming interfaces (API's) that work with modern operating systemsand applications.

The computing system having reduced, i.e., zero latency navigation of UIelements detects and enumerates from a virtualization server as a hostagent and caches at a client computing device selected application UIelements and content metadata, and creates virtual local UI elementsthat are hidden by default and overlay the UI elements at the clientcomputing device. The computing system thus provides an immediatevisible predicted or approximate response to the user input andeventually substitutes that predicted response with the actual responseas a post-response, for example, based on the estimated latency and/orby receiving graphic updates in the area of the user interface in focus.This computing system is advantageous because as more workloads areintegrated into a Cloud network, such as the Citrix Cloud as anon-limiting example, and data centers are consolidated across differentcontinents, the network conditions between the workloads and theendpoints, e.g., a client computing device, become more challenging toimplement and have much higher latency and packet loss. As such, thesystems and methods set forth herein advantageously provide improvedperformance within a virtualized and/or enterprise computingenvironment.

Referring now to FIG. 3 , the computing system in a first aspect isindicated generally at 200 and includes at least one client computingdevice 210 in communication with the virtualization server 214, which isconfigured to run virtual machine sessions and provide a hostedapplication during the virtual machine sessions. The hosted applicationincludes UI elements 218. The client computing device 210 includes aprocessor 220 that is configured to access the hosted application duringone of the virtual machine sessions and receive the UI elements andincludes a display 224, where the UI elements as local virtual UIelements 226 are initially displayed. The processor 220 includes a cachememory 222 to hold UI elements. The user will input data and a displayedpredicted response 228 will be shown based on user input, which could befrom a user input device 229 such as a keyboard, mouse, touch pad, penor other user input device. The client computing device 210 sends userinput to the virtualization server 214, which applies the received userinput to the hosted application and processes the data and generates aset of data, which corresponds to an updated UI element graphics 230,corresponding to an actual response to the user input. Thevirtualization server sends the data as the updated UI element graphics230 to the client computing device 210, which replaces at least aportion of the local virtual UI element graphics overlay correspondingto the predicted response on the display 224 with the data received asthe updated UI element graphics corresponding to a display of the dataas the actual response 234 to the user input.

Referring now to the flowchart in FIG. 4 and generally speaking, amethod for operating a client computing device 210 that includes thedisplay 224 and processor 220 are discussed in conjunction with thevirtualization server 214 and illustrated at 250. From the start (Block252), the method includes receiving UI elements at the client computingdevice 210 after accessing the hosted application having UI elementsduring one of the virtual machine sessions (Block 254), and displayingthe UI elements as local virtual UI elements (Block 256). The methodcontinues by applying the user input to a local virtual UI element infocus (Block 258) and generating a local virtual UI element graphicsoverlay for display corresponding to a predicted response to the userinput from the virtualization server and sending that user input to thevirtualization server (Block 260), which will apply it to the hostedapplication. In response, the method continues with the virtualizationserver 214 generating an updated UI element graphics corresponding to anactual response to the user input from the virtualization server andsending the updated UI element graphics to the at least one clientcomputing device (Block 262). At that time, the client computing deviceis operative for replacing the local virtual UI element graphics overlaywith at least a portion of the local virtual UI element graphics overlaythat corresponds to the predicted response with the received updated UIelement graphics corresponding to the actual response to the user input(Block 264). The method ends at Block 266.

This first aspect described generally at FIGS. 3 and 4 is also directedto a non-transitory computer readable medium for operating thevirtualization server in communication with the virtual machine sessionsprovided by at least one client computing device 210 and providing ahosted application that includes user interface (UI) elements and withthe non-transitory computer readable medium having a plurality ofcomputer executable instructions for causing the at least one clientcomputing device 210 to perform steps that include accessing the hostedapplication from the at least one client computing device during one ofthe virtual machine sessions and receiving the UI elements 218,displaying the UI elements as local virtual UI elements, applying userinput to one of the local virtual UI elements in focus, and generating alocal virtual UI element graphics overlay for display corresponding to apredicted response to the user input from the visualization server. Inresponse to the visualization server updating UI element graphics, thenon-transitory computer readable medium causes at least one clientcomputing device 210 to be operative for receiving the updated UIelement graphics and replacing at least a portion of the local virtualUI element graphics overlay corresponding to the predicted response tothe user input with the received updated UI element graphicscorresponding to the actual response to the user input.

In operation of the computing system 200, further functionalenhancements of the reduced latency navigation may occur whereinreplacement of the local virtual UI element graphics overlay with thereceived updated UI element graphics may be performed by hiding the saidlocal virtual UI element graphics overlay and unveiling the saidreceived updated UI element graphics underneath the said local virtualUI element graphics overlay. In an example, all of the local virtual UIelement graphics overlay may be replaced with the received updated UIelement graphics. This replacing at least a portion of the local virtualUI element graphics overlay with the received updated UI elementgraphics may be based on an estimated latency between the virtualizationserver 214 and the at least one client computing device 210, forexample, at least one of an average, a median, and a standard deviationof latencies between the visualization server and the at least oneclient computing device. The replacing may also be based on one or moreof receiving the updated UI element graphics, heuristics specific toreceiving the updated UI element graphics, and policies associated withdisplaying the received updated UI element graphics.

The UI elements may include metadata, such as encrypted text, andinclude at least one of UI automation properties and events retrievedfrom the hosted application. The local virtual UI element graphicsoverlay may be deleted based on one or more of replacing the said localvirtual UI element graphics overlay with the received updated UI elementgraphics, a hosted application process terminating, a hosted applicationwindow closing, a hosted application UI element getting out of focus, ahosted application UI element becoming hidden, a hosted application UIelement being deleted, heuristics specific to receiving the hostedapplication UI element, and policies associated with displaying thereceived hosted application UI element.

A second aspect of the computing system is shown in FIG. 5 anddesignated generally at 300, and for purposes of description, componentsin this computing system common with those components in FIG. 3 aregiven the same numerical indicia, but described in the 300 series. Theclient computing device 310 includes its processor 320 and furthermore acache memory 322 to hold scrollable content. The virtualization server314 includes the hosted application 318 with its UI elements havingscrollable content. At the client computing device 310, the display 324shows scrollable content 326 as received from the virtualization serverand shows the predicted response 328 to user input 329, based on thescrollable content, and in sequence, shows the actual response 334 asdata received from the virtualization server 314 based on scrollablecontent. The virtualization server 314 processes user input andgenerates data as a updated UI elements 330 having scrollable contentthat is sent to the client computing device 310 to show on the display324 as the actual response 334.

Referring now to the flowchart in FIG. 6 , the method for operating theclient computing device 310 using the computing system 300 of FIG. 5 isillustrated generally at 350. The method starts (Block 352) and includesreceiving the UI elements having scrollable content at the clientcomputing device after accessing the hosted application (Block 354). Themethod further includes displaying the scrollable content as localvirtual UI elements (Block 356) and applying the user input to ascrollable portion of the scrollable content in focus (Block 358). Themethod includes caching the scrollable content adjacent to a portion ofthe scrollable content being scrolled that is not in focus (Block 360),followed by generating local virtual UI element graphics overlay havinga portion of scrollable content as a predicted response to the userinput and sending the user input to the virtualization server (Block362). The method ends at Block 364.

Referring now to FIG. 7 , the method of operating the visualizationserver 314 in the computing system 300 shown in FIG. 5 is illustrated at370. The process starts (Block 372) and the virtualization server 314 isoperative for applying the received user input to the hosted applicationat the virtualization server (Block 374) and then generating updated UIelement graphics having cached scrollable content for an actual responseto user input (Block 376). The method continues with the virtualizationserver sending the updated UI element graphics having cached content toa client computing device (Block 378). The process ends at Block 380.

The estimated latency times as described relative to the computingsystem 200 in the first aspect shown at FIG. 3 also applies whenoperating the computing system 300 and navigating UI elements havingscrollable content. Metadata may be associated with the scrollablecontact and may include text, including at least one of a grid item,table item, spreadsheet item, list item, and data item, and encryptedtext in another example. The scrollable content may be at least one ofvertically scrollable content and horizontally scrollable content thatincludes a scroll pattern and at least one of a text pattern, gridpattern, table pattern, spreadsheet pattern, and a list pattern.

Another aspect is directed to a non-transitory computer readable mediumfor operating virtual machine sessions provided by a virtualizationserver 314 in communication with at least one client computing device310 and providing a hosted application that includes UI elements havingscrollable content that are displayed at the client computing device.The non-transitory computer readable medium has a plurality of computerexecutable instructions for causing the client computing device 310 toperform steps, including accessing the hosted application during one ofthe virtual machine sessions for receiving the UI elements havingscrollable content, displaying at least a portion of the scrollablecontent as local virtual UI elements, applying user input to scroll theportion of the scrollable content in focus, caching scrollable contentthat is positioned adjacent the portion of the scrollable content beingscrolled that is not in focus, generating a local virtual UI elementgraphics overlay that includes at least a portion of the cachedscrollable content for display corresponding to a predicted response tothe user input and sending the user input to the virtualization server.

Referring now to FIG. 8 , there is illustrated a third aspect of thecomputing system and illustrated generally at 400, and for purposes ofdescription, functional components in this computing system common withthose components in FIG. 3 are given the same numerals indicia, butdescribed in the 400 series. The processor 420 at the client computingdevice 410 includes a cache memory 422 that contains graphical controlelements. The virtualization server 414 has a hosted application thatincludes UI elements 418 having an ordered hierarchy of graphicalcontrol elements when sequenced therethrough. The display 424 at theclient computing device 410 displays data corresponding to an orderedhierarchy of graphical control elements 426 and will display data as apredicted response 428 to user input such as typing or other user inputon the input device 429, based on the next graphical control element inthe ordered hierarchy. The virtualization server 414 receives the userinput and processes it to obtain data for the updated UI elementgraphics 430 as the next graphical control element in the orderedhierarchy. The display 424 at the client computing device 410 shows datafor the actual response 434 from the virtualization server 414 based onthe next graphical control element in the ordered hierarchy whensequenced therethrough.

Referring now to the flowchart in FIG. 9 , detailed steps for operatingthe client computing device 410 are discussed and illustrated at 450.From the start (Block 452), the method includes receiving UI elementshaving an ordered hierarchy of graphical control elements when sequencedtherethrough (Block 454). The client computing device 410 is operativefor displaying the ordered hierarchy of graphical control elements aslocal virtual UI elements after accessing the hosted application (Block456) and applying user input to a graphical control element in focus(Block 458). The client computing device 410 is further operative forgenerating a local virtual UI element graphics overlay having the nextgraphical control element in the ordered hierarchy as a predictedresponse to user input and sending the user input to the virtualizationserver 414 (Block 460). The process ends (Block 462).

Referring now to FIG. 10 , detailed steps for operating thevirtualization server 414 of the computing system 400 are discussed andillustrated at 470. From the start (Block 472), the method includesapplying the received user input to the hosted application at thevirtualization server 414 (Block 474) and generating an updated UIelement graphics as a next graphical control element in the orderedhierarchy for the actual response to user input (Block 476). The methodfurther includes sending the updated UI element graphics to the clientcomputing device 410 (Block 478). The process ends (Block 480).

Further enhancements in operation of the computing system 400 having theUI elements and graphical control elements include replacing at least aportion of the local virtual UI element graphics overlay with thereceived updated UI element graphics. This function is similar asdescribed relative to the computing systems 200 and 300 in FIGS. 3 and 5, and may include hiding the said local virtual UI element graphicsoverlay and unveiling the said received updated UI element graphicsunderneath the said local virtual UI element graphics overlay. Theestimated latency between the virtualization server 414 and the at leastone client computing device 410 can be similar to those latenciesdescribed about the previous computing systems 200 and 300. The clientcomputing device 410 includes an input device 429 and with the userinput being based on at least one of a user selecting tab, button, menu,jump list, toggle, and picker control via the input device. In anexample, the next graphical control element in the ordered hierarchyafter the graphical control element receiving the user input may bedisplayed as a highlighted rectangle on the at least one clientcomputing device 410. This highlighting may be based on at least one ofa border and color. The graphical control element may have dataassociated therewith with the data being cached within the cache memory422 at the at least one client computing device 410. The caching by theat least one client computing device 410 may be performed when thecorresponding graphical control element is in focus. For example,caching may be performed when a graphical control element of type combobox or picker control is in focus. In this example, the cachingadvantageously allows subsequent requests by the user to enumerate theoptions presented by a combo box or picker control and to make aselection to be fulfilled with reduced, i.e. zero latency. In otherembodiments or depending on the type of graphical control element, thecaching by the at least one client computing device 410 may be performedeven when the corresponding graphical control element is not in focus.For example, caching may be performed for a graphical control element oftype start menu or jump list even when the graphical control element isnot in focus. In this example, the caching advantageously allows theuser to enumerate the options presented by a start menu or jump list andmake a selection immediately upon the corresponding graphical controlelement receiving focus, i.e. with zero latency. This cached data mayinclude encrypted text such as at least one of a list item, pickercontrol item, menu item, jump list item, and start menu item.

Similar to the functionality of the computing systems 200, 300 describedabove, the local virtual UI element graphics overlay may be deletedbased on one or more of replacing the said local virtual UI elementgraphics overlay with the received updated UI element graphics, hostedapplication process terminating, hosted application window closing,hosted application UI element getting out of focus, hosted applicationUI element becoming hidden, hosted application UI element being deleted,heuristics specific to receiving the hosted application UI element, andpolicies associated with displaying the received hosted application UIelement.

Another aspect of this computing system 400 is directed to anon-transitory computer readable medium for operating virtual machinesessions provided by a virtualization server 414 in communication withat least one client computing device 410 and providing a hostedapplication that includes UI elements 418 comprising an orderedhierarchy of graphical control elements when sequenced therethrough.This non-transitory computer readable medium has a plurality of computerexecutable instructions for causing the client computing device 410 toperform steps, including: accessing the hosted application during one ofthe virtual machine sessions for receiving the UI elements comprising anordered hierarchy of graphical control elements when sequencedtherethrough, displaying the ordered hierarchy of graphical controlelements as local virtual UI elements, applying user input to one of thegraphical control elements in focus, generating a local virtual UIelement graphics overlay for display corresponding the a predictedresponse to the user input, with the predicted response corresponding toa next graphical control element in the ordered hierarchy after thegraphical control element receiving the user input, and sending the userinput to the virtualization server 414.

These computing systems 200, 300, 400 as described above relative to thespecific examples that reduce latency to what appears to the user to bea zero latency, include use of the cloud-based services such as theCitrix Cloud, which can be prone to latency issues, and thus, addressthe latency by reducing latency in the navigation of the UI elements towhat appears to be a zero latency to the user. These latency issues areoften apparent in Cloud-based systems and are now described in greaterdetail to obtain a better understanding of the advantageous functionsresulting from these computing systems 200, 300, 400 described above.Unless otherwise indicated, the reference numerals for the computingsystem 200, client computing device 210, virtualization server 214, andtheir functionality are described but basic functions apply, of course,with computing systems 300, 400 shown in FIGS. 5 and 8 .

As used herein, the term cloud may refer to the Citrix Cloud as aplatform that allows organizations to deploy cloud-hosted desktops andapplications to end users or any other cloud based systems. For example,Citrix Systems' XenApp Essentials delivers Windows-based applicationsand shared, hosted desktops to any user on a client computing device 210and provides as a service the consolidated remote access to cloud-basedworkloads of desktops and applications, or a hybrid combination of thecloud network and on-premises workloads with a consolidated interface.In addition, the Citrix Systems' Gateway as a Service (GWaaS), alsoreferred to as the NetScaler Gateway Service (NGS), allows users toaccess remotely both the Cloud and on-premises workloads without settingup a specific customer on a gateway located at the premises. However, asthe network “hops” to and from the Cloud, this “hopping” action furtherincreases the network latencies between a virtualization server 214 andclient computing device 210, creating a poor user experience andassociated problems when navigating the UI elements, such as by tabbingor scrolling. As a result, the user experience working remotely isdramatically impaired. The computer system 200 with reduced, i.e., zerolatency navigation of UI elements addresses and solves this latencyproblem as noted above, and can best be evident when looked at inrelation to a chart of latencies or round trip times in a system.

Referring now to FIG. 11 , there is illustrated at 490 the ICA(Independent Computing Architecture) Round-Trip Time (RTT) for differentNGS Points of Presence (POPs) based on a geographic location, showinghow the different aspects of the computing system 200 disclosed aboveare beneficial since the lag time is reduced when using the computingsystem for reduced, i.e., zero latency navigation of UI elements. In thegraph of FIG. 11 , the different measurements are based on an HDXsession over TCP as the transport protocol. Citrix Systems' HDXtechnology provides the high definition user experience of virtualdesktops similar to a remote display protocol and includes the ICAprotocol. The ICA RTT measures the inter-activity of the HDX session asa click-to-photon rate, which is the time difference between a userinput event, such as the user's input on a keyboard, mouse or touch pad,and the corresponding graphics update generated by the hostedapplication and delivered at the client computing device 210. Asillustrated, without using the improvements derived from computingsystems with the reduced, i.e., zero latency navigation of UI elementsdescribed above, the lag time is not inconsequential and results insevere degradation of the user experience at a client computing device210. Also, it should be understood that the ICA RTT is not necessarilyequal to the network layer 7 latency because ICA RTT can be influencedby the application response time, the server load and other factors.

The user experience with Asia-Pacific workloads is particularlychallenging since the lag time is high as illustrated at the bar chartat 492 (az-jp-e). Even in the United States, over 50% of the connectionsincur an ICA RTT of 100 ms or higher such as the az-us-w or az-us-scillustrated at the bar charts at 494. There are additional cases ofusers in remote branch office locations using a VSAT (very smallaperture terminal) as a satellite communications system and havingconnections with 1000-2000 ms latency. In addition, high resolutionmonitors, e.g., about 4K, and other multi-monitor displays will makegraphic loads have an even higher latency, further diminishing the userexperience when operating remotely. Conversely, when using mobiledevices, while resolutions are lower, there is an expectation ofnative-like application responsiveness when remotely connected. Thecurrent user experience without the reduced, i.e., zero latencynavigation of UI elements, “lags” in normal office workloads such astyping, mouse or touch window dragging, scrolling, application switchingand similar functions. The user experience also “lags” when usingthree-dimensional gaming software while interacting with complex 3Dgraphics models, and when using Virtual Reality (VR) applications whenremote, such as with the Citrix XenApp hosted applications.

The computing systems 200, 300, 400 as described allow reduced, i.e.,zero latency navigation of UI elements to the point where a userbelieves they are experiencing no latency. Benefits in improving latencydelays have been found in some systems when a shift to UDP (UserDatagram Protocol) as the transport protocol is achieved to overcomesome of the limitations of the TCP (Transport Control Protocol). It isknown that TCP uses the Additive Increments Multiplicative Decrements(AIMD) congestion control algorithm, but it cannot fully use thebandwidth in conditions of latency and loss. In modern networks, thebandwidth tends to be more plentiful and packet loss occurs primarilydue to endpoint interference and stochastic loss and not congestion.Therefore, some packet loss can be tolerated without drasticallyreducing throughput. For example, different software manufacturerproduct families are migrating to QUIC as an experimental transportlayer network protocol designed by Google. The Citrix Systems' HDX hasrecently introduced the Enlightened Data Transport (EDT) protocol, whichis a reliable-transmission UDP-based protocol that has better congestionand flow control than TCP in challenging network conditions. For atypical transoceanic WAN (Wide Area Network) of 250 ms RTT and 1% packetloss each way, the HDX over EDT as a transport mechanism performs betterthan that over TCP, and thus, may allow a better reduced latencynavigation of UI elements in the example computing systems 200, 300,400. The interactivity is up to 2.5 times better, depending on theworkload, such as scrolling text in a Notepad program vs. a webpage withimages. It is also better because of the client drive mapping (remotefile copy), e.g., up to a tenfold improvement, and with printingimproved two-fold. A generic USB redirection may have up to a 35%improvement. The more stream-oriented and less interactive the remotingtechnology, the higher the benefits of the EDT.

While the EDT benefits ICA virtual channels, there is still room forimprovement, which is provided by the reduced, i.e., zero latencynavigation of UI elements as described above. EDT is a reliableprotocol, but any loss results in packet retransmissions, whichinvariably limits the user experience. Improvements in a default displayremoting technology such as Citrix HDX Thinwire used with a progressivedisplay for transient regions helps improve the user experience, but theuser experience is still limited by the nature of the underlyingtransport protocol.

Commonly assigned provisional patent application Ser. No. 62/667,072filed on May 4, 2018, the disclosure which is hereby incorporated byreference in its entirety, discloses a remote computing system thatoptimizes region detection, classification and update prioritization,using a hierarchical display with optimized graphics for remotecommunication in challenging network conditions, including thoseconditions having high latency and/or loss, to achieve betterinteractivity but at the expense of fidelity with a lossy transmissionor a combination of reliable and lossy transmissions in some areas.Interactivity may be improved when Forward Error Correction (FEC) isapplied to reliable transmissions, but there will be some trade-off inthe overall bandwidth and processing efficiency. That type of remotecomputing regains fidelity when using FEC in those areas having lossytransmissions, and for that reason, achieves a better quality along withimproved interactivity from the client computing device at the expenseof some bandwidth and CPU. The optimal FEC algorithm is selected basedon expected bit rate, percentage loss and other similar factors. Userinput is transmitted with aggressive FEC to optimize the transmissionand avoid retransmission delays with negligible impact on the bandwidth.Yet even with these improvements, the user experience is much betterwhen used in conjunction with the computing systems 200, 300, 400 asdescribed.

Although there are improvements for interactivity as described above,that type of remote computing disclosed in the '072 application, evenwhen using an optimal and aggressive FEC, does not do better than theunderlying RTT, i.e., the system cannot physically do better when itcomes to delivering the true updates from the hosted application. Inaddition, some users in remote branch office locations use VSATconnections with as much as a 1000-2000 ms latency, where the existingtechniques or systems are not always sufficient for an adequate userexperience, and thus, the remote computing systems 200, 300, 400 asdescribed could be implemented to improve the user experience and allowa reduced, i.e., zero latency navigation of UI elements.

In addition to the traditional local text echo for typing as disclosedin the incorporated by reference and commonly assigned '667 patent, thecomputing systems 200, 300, 400 operate to reduce the latency innavigation of UI elements and provide localized and more robustnavigation for actions such as tabbing, scrolling, navigating gridcontrols, opening and selecting from picker controls, menus and similaruser input functions. Although these user actions or functions may notwork for all possible applications, the computing systems 200, 300, 400as described optimize most common use cases and applications as permitsa reduced latency navigation of UI elements, which to the user appearsas a zero latency.

Referring now to FIG. 12 , there is illustrated a sequence diagramshowing the general data flow that is applicable to the computingsystems 200, 300 and 400 in the three aspects described at FIGS. 3, 5and 8 , and having the reduced, i.e., zero latency navigation for thevirtual applications. For simplicity in description, the data flow isexplained relative to the client computing device 200 of FIG. 3 . A user(U) is shown diagrammatically at the top left adjacent a client deviceas the client computing device 210. The user (U) inputs data into theclient computing device 210, which includes a display 224 and operativeas the illustrated graphics display window and showing the UI element 1′(225) and the UI element N′ (226) that are displayed and operative witheach other via the virtual overlays such as described above. The clientcomputing device 210 includes in this example a client agent 227 as aninterface or communications agent described generally above also withreference to FIGS. 1 and 2 . The virtualization server 214 operates as ahost and includes a host agent 215 operative as a communicationsinterface such as described relative to FIGS. 1 and 2 , and whichcommunicates with the client agent 227, and further includes a SessionDesktop (running as the Root UI Element 218) of a hosted applicationwith the illustrated UI Element 1 (216) and UI Element N (217). In thisdescription of FIG. 12 , the data flow sequence extends downward,vertically in time as the sequence diagram.

Communication is initiated between the interfaces at the clientcomputing device 210 and virtualization server 214 as the respectiveclient agent 227 and the host agent 215. The latency in communication isdetected, which could include a latency standard deviation abovepredetermined levels or an average or median as non-limiting examples asdiscussed above. The host agent 215 enumerates the hosted applicationprocesses and windows and enumerates the UI elements, their properties,and a hierarchical view for some graphical control elements with respectto the computing system 400 shown in FIG. 8 . The host agent 215 at thevirtualization server 214 sends the UI elements metadata, including anyhierarchical controls for viewing content to the client agent 227, whichcreates the hidden or virtual overlay as local UI elements. These arehidden by default and overlay the graphics' windows as displayed at theclient computing device 210. The user provides input to the client agent227 such as a tab, scroll or other input, which is made visible. Theuser input and the UI element are revealed as a visible overlay to thegraphics at the display 224 as an immediate predicted (approximate)response to the user input. The client agent 227 sends the user input tothe host agent 215, which applies (injects) asynchronously over a highlatency network the user input to the hosted application. Thevirtualization server 214 responds to the user input, including anygraphics update and the host agent 215 sends the graphics update to theclient agent 227, which renders and reveals host graphics as updatedgraphics in local display windows. This is the actual applicationresponse as the observed application response. In this part of the flowsequence, the client agent 227 hides some or all the local virtual UIelement overlay and reveals beneath the graphics of the actualapplication response. The timing of the disappearance or phase-out ofthe local virtual UI element overlay may depend on any combination ofthe estimated latency, the estimated latency standard deviation, thereceiving of graphics updates in the area of the UI element in focus,the heuristics specific to the UI element patterns, the administrationor user policy and similar policies as addressed above. Thevirtualization server 214 works asynchronously and the applicationprocess and/or window closes and the host agent 215 detects removal. Inresponse, the host agent 215 sends a destroy command to the client agent227 and also sends asynchronously the graphics update. The client agent227 destroys the virtual local user interface elements and rendersasynchronously the graphics.

To optimize the host processing and network traffic, the UI elements maybe created only for any applications in focus, although this may reduceresponsiveness immediately after bringing a new window in focus anduntil the new UI elements are cached at the client computing device 210,especially with reference to UI elements having scrollable data in thecache 322 or with graphical control elements in the cache 422. Somemetadata may be sent to the client computing device 210, e.g., text, andit may be additionally encrypted for security, both in transit and atrest.

The computing system 200 as described allows reduced, i.e., zero latencynavigation of UI elements, and includes Application ProgrammingInterfaces (API's) that have different features, including virtualwindow tracking in some applications. For example, the Seamless AppSupport Virtual Channel (VC) subsystem supplied by Citrix Systems mayenumerate and track updates at top-level windows. It may also includeVirtual App (application) process monitoring, for example, as providedby a process monitoring driver used by the Seamless App Support VCsubsystem supplied by Citrix Systems. Different patterns, properties andevents may be retrieved from hosted applications or a desktopenvironment, for example, as based on the Microsoft UI Automation API(Application Programming Interface), which is the successor of theMicrosoft Active Accessibility API, as found inhttps:\\msdn.Microsoft.com\EN-US\library\windows\desktop\EE684009(v=vs.85).aspx.In particular, an application programming interface at thevirtualization server 214 enables applications to interact with controlsand other applications and retrieve information about them. The hostagent 215 in the HDX session may use the Microsoft Active AccessibilityAPI as a client to retrieve information about hosted applications andthe desktop. The host agent 215 may register for specific eventnotifications and can request that the specific UI automation propertiesand control pattern information be passed into its event handlers. A UIautomation API may be used to enumerate elements starting from thedesktop as the root of the hierarchy, or from any window or current UIelement in focus, which may be a data container for additional elements.The UI Automation API as supplied by Microsoft may be used to identifyprocesses and windows as an alternative to the Seamless App Support VCsubsystem. The Seamless Subsystem itself may be efficiently implementedbased on the UI Automation API. For example, the Seamless Subsystem mayregister for the following events using the UI Automation API providedby Microsoft: WindowPattern.WindowOpenedEvent,WindowPattern.WindowClosedEvent. The Seamless Subsystem could also queryAutomationElement.ProcessIDProperty,AutomationElement.NativeWindowHandleProperty. The remote applicationprotocol may include process Identifiers (IDs) and window IDs forpurposes of supporting both Seamless Applications and a Desktop Windowmode. Local virtual overlays may be scaled or panned to account forwindow scaling, panning and resolution differences (Dots Per Inch (DPI))between the client and host environments, e.g., based on the CitrixSystems' Receiver Window Positioning APIs. The network latency andlatency standard deviation could be measured by the HDX transport driverprovided by Citrix Systems, Inc. It should be understood that the HDXThinwire as a Citrix XenApp Virtual Channel (VC) may operate forgraphics remoting between the virtualization server 214 and the clientcomputing device 210.

The computing system 200 handles UI element patterns and may alsoinclude an improved text echo with the host agent 215, for example,detecting the focus in a text element, e.g., exhibiting a pattern forthe text and sending the cursor position and rich font information tothe client computing device 210. For example, the pattern for the text,also termed TextPattern as a data item, may include various attributesor elements that are categorized as various data items:FontSizeAttribute; FontNameAttribute; MixedAttributeValue;FontWeightAttribute (thin, light, normal, medium, bold, heavy, etc.);IsItalicAttribute; IsSuperscriptAttribute; ForegroundColorAttribute;BackgroudColorAttribute; BulletStyleAttribte;HorizontalTextAlignmentAttribute; IndentationLeadingAttribute;IndentationTrailingAttribute; MarginTopAttribute;MarginTrailingAttribute; IsHiddenAttribute; TextFlowDirectionsAttribute(Default: Top to bottom, left to right, horizontal); and similarattributes.

The client computing device 210 may present a virtual local UI elementoverlay of the type text field, located at a respective cursor position,and with the font consistent with the received font attributes. As theuser types on the input device 229, the client computing device 210provides immediate text response in the overlay field. As noted before,a general explanation of simplified local text echo is described in theincorporated by reference and commonly assigned '667 patent, but thereduced, i.e., zero latency navigation of the computing system 200improves this text echo by supporting both Seamless Apps and Desktopmode, panning, scaling, DPI differences and similar functional items.The computing system 200 may account for text container margins and notgoing beyond margins.

For example, while typing towards the end of the line in a textdocument, the computing system 200 may avoid going off the right end ofthe visible page. The expected behavior is wrapping around to a newline. This can be achieved based on knowledge of container margins,complete font information such as line spacing, indentation and similaritems with sufficient surrounding text context. For example, thesurrounding text can be retrieved by means of the data items and programroutines associated with a TextRange control pattern using the textpattern.range from point API, TextPatternRange.ExpandToEnclosingUnit APIor other related APIs, and specifying the amount by which to move orchange the size of the text range in units (TextUnit) of character andformat where the text shares all the same attributes. This also mayinclude a word, line, paragraph, page or a whole document. The computingsystem 200 may send and cache at the client computing device 210sufficient text context around the cursor focus to allow for localauto-correction of typed text and the proper letter capitalization, wordcorrection or suggestions. The computing system 200 may take intoaccount the boundary of an embedded object such as an image orhyperlink.

The computing system 200 may also provide for tab stops with therespective correct positions for tab stops occurring by enumeratingthem. For example, it is possible to use a GetAttributeValue API asprovided by Citrix Systems to retrieve the TextPattern.TabsAttribute asa collection of tab stops and points and associated with variousgraphics. It is possible to determine if the UI element content isprotected, for example, using a password field, based on a data andprogram routine AutomationElement.ISPasswordProperty. The clientcomputing device 210 may then provide a local overlay with an asteriskand additionally encrypt the text sent to the virtualization server 214.

Referring now to FIG. 13 , there is illustrated an example screenshot at500 as an example for the application of the reduced, i.e., zero latencynavigation of UI elements and showing the automation and retrieving oftext, such as a word scope, and the font properties under the cursor inan example Notepad program. The font and text properties such as fontsize and font type are described generally at the left at 502 with ageneral description labeled as Font Size and Font Type Properties forText and Data, but would in an actual screenshot include a completelisting of such properties and displayed to the user in this example.

Referring now to FIG. 14 , there is another example screenshot 510similar to that screenshot of FIG. 13 , but having automation andretrieving of text (word scope) and having font properties under thecursor in an example Microsoft Word program. Similar as in FIG. 13 , ageneral description is given of the font size and font type propertiesgenerally at the left at 512.

Referring now to FIG. 15 , there is illustrated another screenshot at520 and similar to that of FIGS. 13 and 14 , but showing automation andretrieving of text (word scope) and font properties under the cursor inan example Microsoft Excel program. Again as in the previous twoscreenshots of FIGS. 13 and 14 , the font type and font size propertiesare shown generally at 522 on the left. Those three screenshots arenon-limiting examples that illustrate the wide variety of potentialapplications when incorporating the reduced, i.e., zero latencynavigation of UI elements.

The computing system 300 in a second aspect as described above mayinclude window and container scrolling with or without text. Referringnow to FIG. 16 , there is illustrated generally at 530 a fragmentarygraphical diagram of a Window/Container Scrolling operation using cachedcontent in a document, such as displayed at a user operated computer,and showing Cached Content 1 at Time 1 on the left and adjacent on theright the Cached Content 1 and the scroll down at Time 2. At Time 1,there is illustrated the Cached Content 1, Graphics Region 1, GraphicsRegion 2, and Cached Content 2, and on the right for the scroll down atTime 2, there is shown the Cached Content 1 and what amounts to afunctional screen-to-screen copy for the Graphics Region 2 and theGraphics Region 3 that is derived from the Cached Content 2 based atTime 1 and the Cached Content 2. This fragmentary graphical diagramshows that at least a portion of the scrollable content can be displayedas the local virtual UI elements and the client computing device 310 mayscroll a portion of the scrollable content in focus and then cache thescrollable content that is positioned adjacent the portion of thescrollable content being scrolled that is not in focus corresponding tographics regions such as from the cached content as illustrated.

Referring to FIG. 17 , another example of a screenshot at 540 shows anexample of retrieving text (the entire document scope) and fontproperties under the cursor in Microsoft Word as illustrated and showsan example of what would be the full text on the left where a portioncould be selected for scrolling and labeled as “Full Text Section ForScrolling” at 542 giving an example of program and data as displayed.

Referring to FIG. 18 , a fragmentary drawing of a screenshot isindicated generally at 550 as an example of window/container scrollingusing cached content as Start Menu items. Various icons are representedgenerally by the logo icons, indicative that icons would be displayed atthat location in an actual screenshot of a Start Menu. These twoscreenshot views 540, 550 at FIGS. 17 and 18 illustrate the potentialapplications for the scrolling operation to reduce to what appears to bezero latency in the navigation of UI elements, where for the user, theexperience is that of a zero latency navigation.

An example explanation for window/container scrolling with text is nowdescribed. Reference may be made to the details in the high level flowsequence of data explained at FIG. 12 , but with reference to scrollingusing the computing system 300 as described above. The client computingdevice 310 detects a container in focus with the scroll pattern and anembedded text pattern. For example, the virtualization server 314 mayreceive data and listen as the client computing device 310 processesdata items as ScrollPattern and/or ScrolltermPattern events and propertyupdates. The virtualization server 314 detects an embedded TextPatternas data. The client computing device 310 queries the UI elementexhibiting the ScrollPattern and determines old and new values forwhether the UI control is horizontally and/or vertically scrollable, anddetermines horizontal and vertical view sizes and horizontal andvertical scroll percentages. For example, in the computing system 300,the virtualization server 314 may retrieve values as identified by dataitems as the VerticallyScrollableProperty, VerticalViewSizeProperty, andVerticalScrollPercentProperty.

The virtualization server 314 may query the UI element exhibiting thetext pattern by determining a text range within the element that iscurrently in view, for example, using routines such as described as anIUIAutomationTextRange:GetAttributeValue API with attribute parametersset to a data item as UTA_IsHiddenAttributeId. It is then possible toretrieve a text range currently beyond the view, for example, thesurrounding text could be retrieved by means of the TextRange controlpattern using different API's, including the TextPattern.RangeFromPointAPI, the TextPatternRange.ExpandToEnclosingUnit API or other relatedAPIs and specify the amount by which to move or change the size of atext range in units (Text Unit) of the character and format where alltext that shares all the same attributes include word, line, paragraph,page or a whole document.

It is possible to have the UI element metadata sent from thevirtualization server 314 to the client computing device 310, and thismetadata may include the scroll pattern UI element properties describedabove. It may also include a range of text content beyond the currentlyvisible area, e.g., several paragraphs or pages above or below thecurrent view of the vertically scrollable content. It is possible tosend the actual text with text attributes, including the font type, fontsize, foreground/background color, italic, bold, underline, line spacingand similar text attributes. The client computing device 310 may createthe virtual local UI elements overlaying a corresponding local displaywindow that are hidden by default. When the user scrolls, the clientcomputing device 310 in effect performs a local screen-to-screen copy ofthe scrolled area such as shown and described relative to thewindow/container scrolling of FIG. 16 . The client computing device 310also performs a local fill of the exposed area with the previouslycached content such as the text and attributes. Eventually the computingsystem 300 via the virtual server 314 displays the actual applicationresponse to the scrolling.

Rather than sending text with attributes, the virtualization server 314may enumerate the scroll items (ScrollItemPattern) and send them asindividual items to the client computing device 310 to be presented withwhat appears to be zero latency to the user when they move into view. Anexample includes scroll items in a list control (List), for example, thesystem Start Menu as in FIG. 18 , where there may be zero or more itemsas data, zero or more items in a list, and zero or more data groups.Another example includes data items (DataItem, GridItemPattern) in agrid control (Data Grid, Grid Pattern), e.g., which could correspond tothe next rows in a spreadsheet worksheet. Another example could useGridPattern.GetItem API as provided by the UI Automation API.

Referring now to FIG. 19 , there is illustrated an example of tab ordernavigation such as processed at the computing system 400 (FIG. 8 ) andshowing at the client computing device 410 the display 424 as a graphicsdisplay window and a client agent 427 functioning similar to the clientagent described relative to FIG. 12 . There is an immediate local focusshift to a new virtual UI element following the tab order as an examplefor the tab order navigation, while selecting a next graphical controlelement in the ordered hierarchy. The display 424 at the clientcomputing device 410 is operative as a Graphics Display Window andillustrated with Tab K′ 411 as a hidden UI element and interconnected byVirtual Overlays to the next in sequence graphical element as the TabK+1′ 412 and showing diagrammatically by the dotted line the immediatelocal focus shift. This tab order navigation and its data flow is alsodescribed generally relative to the flow sequence of data described inFIG. 12 .

In an example, to determine the tab order, the virtualization server 414initially enumerates UI elements starting at the top-level parent windowas the root element (RootElement) and then enumerates its children in acontrol view. In that enumeration, for example, the children, i.e., inthis example, the next in sequence for a UI as a graphical controlelement as described, could be accomplished using TreeWalker,GetFirstChild and GetNextSibling API's in a remote session applicationand provided by Microsoft. Different commands are deployed as described.The search/walk can be optimized by adding conditions, for example, viaPropertyCondition and AndCondition APIs to enumerate only elements thatare controls, e.g., (AutomationElement.IsControlElementProperty), whichare enabled and (AutomationElement.IsEnabledProperty), which are a tabstop, i.e., it can receive a keyboard focus as a UI element as a tabstop (IsTabStop). The relative tab order of enumerated controls can beretrieved using a defined tab index (TabIndex) of each control incombination with the enumerated order, such as left-to-right andtop-to-bottom, when a specific tab index is not defined. The coordinatesof the rectangle that completely encloses each element may also beretrieved as a BoundingRectangle property. The element with the currentkeyboard focus as a HasKeyboardFocus property is also identified.

The virtualization server 414 inserts the enumerated control elementsalong with their relative tab order in a hierarchal tree, e.g., aTreeNode, and remotes the hierarchy along with its top-level windowhandle to the client agent 427 at the client computing device 410, whichrecreates the tree locally as virtual local UI elements overlaying acorresponding local display window, which are hidden by default. Theclient agent 427 at the client computing device 410 keeps track of thecurrent UI element with the keyboard focus.

When the user enters a “tab” on the input device such as the keyboard,the client agent 427 at the client computing device 410 may perform animmediate keyboard focus switch to the virtual local UI element that isnext in the tab order and makes it visible. This allows the user toimmediately start input into the new virtual local UI element in focus,e.g. a new control UI element, or continue tabbing to the next control,and thus, receive a reduced but what appears to the user to be a zerolatency local feedback.

The user at the client computing device 410 may choose a new UI elementin focus. The client agent 427 at the client computing device 410 mayhighlight it such as by a bounding rectangle. For example, it ispossible to apply a rectangular graphic with a thick and/or blinkingborder, or impart a different color or impart a different distinguishingtechnique to highlight the rectangle. This may be necessary because theactual hosted application response will be delayed, and therefore, thecontrol UI element previously in focus may still show the graphicsimplying the keyboard focus in the regular graphics display, even thoughthe client agent 427 at the client computing device 410 has alreadyswitched the focus with the reduced or what appears to the user to bezero latency to the next local control in the tab order as the nextgraphical control element in the ordered hierarchy. The localhighlighting may stop as soon as the virtualization server 414 reports anew element in focus consistent with the current virtual local UIelement in focus. The computing system 400 may also include navigationin tables, data grid controls and similar functional user input itemswith graphical control elements.

Referring now to FIG. 20 , a graphical table representation of a textcontainer as a document is shown generally at 600, and includes anembedded table 610 and flower image 614. In FIG. 21 , the graphicalcontent view as a hierarchy of this table is shown generally at 620. Theembedded table 610 and flower image 614 in FIG. 20 are non-limitingexamples to illustrate how the text document graphically may contain atable and, in this example, include four headers labeled header 0,header 1, header 2, and header 3, with the different value.

As shown in FIG. 21 , the hierarchy view 620 of graphical controlelements and the different content views of the text container areillustrated with explanations for the type of data. Some navigationssuch as tabbing or using the arrow keys (up, down, left and right) canbe optimized by caching at the client computing device 410 metadataassociated with the UI elements around the current element in focus.Examples include data items that may be labeled DataItem,GridItemPattern in a grid control and labeled DataGrid, GridPattern,e.g., the adjacent cells in a spreadsheet worksheet. Other examplesinclude data items that are labeled DataItem, TableItemPattern in atable control that may be labeled Table, TablePattern, e.g., theadjacent cells in a table in a document. Other examples could use aGridPattern.GetItem API. Similar to the methodology for the tab ordernavigation as described above, focusing a new UI element may requirehighlighting to distinguish it from the residual graphic showing thefocus of the previous UI element.

It is also possible to conduct navigation in picker controls, referredto by some skilled in the art as a combo box, e.g., a list box, combinedwith a static control or edit control that displays the currentlyselected item in the list box portion of the combo box. The list boxportion of the edit control may be displayed at all times or only appearwhen a user selects the drop-down arrow, which can be a push button,next to the edit control. For example, referring now to FIG. 22 , thereis illustrated an example screenshot as a combo box generally at 650 fora Wikipedia webpage as a non-limiting example, and at FIG. 23 , thescreenshot as a combo box is selected in the webpage and shown generallyat 660.

As an example, the client computing device 410 may receive from thevirtualization server 414 metadata associated with a combo box. Uponreceiving user input in the area of a drop-down arrow, the clientcomputing device 410 may immediately display the complete list items(ListItem) in the local virtual UI element overlay. Upon receiving userselection of one of the list items, the client computing device 410 mayimmediately display the selection in a local static/edit control andasynchronously hide the local list box in the local virtual UI elementoverlay.

It is also possible to apply the reduced latency navigation UI elementsas described for opening, closing menus and jump lists using similartechniques as described. Similar to the parameters described relative tothe navigation and picker controls described above, metadata associatedwith menus containing a collection of menu items as UI elements andmetadata associated with different jump lists such as a taskbar, alsoknown as destination lists, could be cached at the client computingdevice 410 to provide immediate local feedback. It is also possible tochange the state of toggle controls such as check boxes or groups ofradio buttons that could be optimized with immediate local feedback in asimilar fashion. For example, an application may use radio buttons in agroup box to permit the user to choose from a set of related, butmutually exclusive options. Therefore, similar to the technique for taborder navigation described above, the computing system may focus in anew UI element as a selected radio button that may need to behighlighted to distinguish it from the residual graphics showing thefocus in the previous UI element.

Many modifications and other embodiments will come to the mind of oneskilled in the art having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it isunderstood that the disclosure is not to be limited to the specificembodiments disclosed, and that modifications and embodiments areintended to be included within the scope of the appended claims.

The invention claimed is:
 1. A computing system operable to run virtualmachine sessions from a virtualization server and provide a hostedapplication, the computing system comprising: at least one clientcomputing device configured to access the hosted application during avirtual machine session and receive a hierarchical tree of userinterface (UI) elements having vertically or horizontally scrollablecontent that includes text and graphics, and configured to perform thefollowing: display some of the UI elements from the hierarchical tree asat least a portion of the vertically or horizontally scrollable contentas local virtual UI elements and based upon the received hierarchicaltree, maintain hidden the other UI elements as scrollable content, applyuser input to scroll a portion of the displayed vertically orhorizontally scrollable content, cache the hierarchical tree ofscrollable content, and generate a local virtual UI element graphicsoverlay and display the local virtual UI elements to which user inputhad been selected and scrolled and one or more previously hidden UIelements as scrollable content corresponding to a predicted response tothe user input; send the user input to said virtualization server, andreceive from the virtualization server an updated UI element graphicsthat includes scrollable content corresponding to an actual response tothe user input and replace at least a portion of the displayed localvirtual UI element graphics overlay that includes at least a portion ofthe cached scalable content with the received updated UI elementgraphics.
 2. The computing system of claim 1 further comprising metadataassociated with the vertically or horizontally scrollable content. 3.The computing system of claim 2 wherein the vertically or horizontallyscrollable content includes at least one of grid item, table item,spreadsheet item, list item, and data item.
 4. The computing system ofclaim 2 wherein the metadata includes encrypted text.
 5. The computingsystem of claim 2 wherein the metadata includes at least one of UIautomation properties and events retrieved from the hosted application.6. The computing system of claim 1 wherein the vertically orhorizontally scrollable content includes the text and graphics and ascroll pattern and at least one of a text pattern, grid pattern, tablepattern, spreadsheet pattern, and a list pattern.
 7. The computingsystem of claim 1 wherein the local virtual UI element graphics overlayis deleted based on one or more of replacing said local virtual UIelement graphics overlay with the received updated UI element graphics,hosted application process terminating, hosted application windowclosing, hosted application UI element getting out of focus, hostedapplication UI element becoming hidden, hosted application UI elementbeing deleted, heuristics specific to receiving the hosted applicationUI element, and policies associated with displaying the received hostedapplication UI element.
 8. The computing device of claim 1 wherein theat least one client computing device is configured to access the hostedapplication based upon a determined latency by the virtualization serverwith the at least one client computing device as a latency standarddeviation above predetermined levels or an average or median latency. 9.The computing device of claim 1 wherein the at least one clientcomputing device is configured to receive an updated UI element graphicsthat includes scrollable content corresponding to an actual response tothe user input and replace at least a portion of the displayed localvirtual UI element graphics overlay that includes at least a portion ofthe cached scalable content with the received updated UI elementgraphics.
 10. The computing system of claim 9 wherein the replacement ofthe at least a portion of the local virtual UI element graphics overlaywith the received updated UI element graphics is performed by hiding thesaid at least a portion of the local virtual UI element graphics overlayand unveiling the said received updated UI element graphics underneaththe said at least a portion of the local virtual UI element graphicsoverlay.
 11. A method for operating virtual machine sessions provided bya virtualization server in communication with at least one clientcomputing device to provide a hosted application that includes userinterface (UI) elements having vertically or horizontally scrollablecontent that includes text and graphics, the method comprising:accessing the hosted application from at least one client computingdevice during one of the virtual machines sessions for receiving ahierarchical tree of the UI elements having the vertically orhorizontally scrollable content, the client computing device operable toperform the following: displaying some of the UI elements from thehierarchical tree as at least a portion of the vertically orhorizontally scrollable content as local virtual UI elements, and basedupon the received hierarchical tree maintaining hidden the other UIelements as scrollable content, applying user input to scroll a portionof the displayed vertically or horizontally scrollable content, cachingthe hierarchical tree of scrollable content, and generating a localvirtual UI element graphics overlay and displaying the local virtual UIelements to which user input had been selected and scrolled and one ormore previously hidden UI elements as scrollable content correspondingto a predicted response to the user input; sending the user input tosaid virtualization server, and receiving updated UI element graphicsfrom the virtualization server that includes scrollable contentcorresponding to an actual response to the user input and replacing atleast a portion of the displayed local virtual UI element graphicsoverlay that includes at least a portion of the cached scrollablecontent with the received updated UI element graphics.
 12. The method ofclaim 11 further comprising metadata associated with the scrollablecontent.
 13. The method of claim 12 wherein the metadata includesencrypted text.
 14. The method of claim 12 wherein the metadata includesat least one of UI automation properties and events retrieved from thehosted application.
 15. The method of claim 11 wherein the vertically orhorizontally scrollable content includes the text and graphics and ascroll pattern and at least one of a text pattern, grid pattern, tablepattern, spreadsheet pattern, and a list pattern.
 16. The method ofclaim 11 wherein the local virtual UI element graphics overlay isdeleted based on one or more of replacing the said local virtual UIelement graphics overlay with the received updated UI element graphics,hosted application process terminating, hosted application windowclosing, hosted application UI element getting out of focus, hostedapplication UI element becoming hidden, hosted application UI elementbeing deleted, heuristics specific to receiving the hosted applicationUI element, and policies associated with displaying the received hostedapplication UI element.
 17. The method of claim 11 wherein the localvirtual UI element graphics overlay is generated based upon a determinedlatency by the virtualization server with the at least one clientcomputing device as a latency standard deviation above predeterminedlevels or an average or median latency.
 18. The method of claim 11wherein the at least one client computing device is operative forreceiving updated UI element graphics from the virtualization serverthat includes scrollable content corresponding to the actual response tothe user input and replacing at least a portion of the displayed localvirtual UI element graphics overlay that includes at least a portion ofthe cached scrollable content with the received updated UI elementgraphics.
 19. The method of claim 18 wherein the replacement of the atleast a portion of the local virtual UI element graphics overlay withthe received updated UI element graphics is performed by hiding the saidat least a portion of the local virtual UI element graphics overlay andunveiling the said received updated UI element graphics underneath thesaid at least a portion of the local virtual UI element graphicsoverlay.
 20. A non-transitory computer readable medium for operatingvirtual machine sessions provided by a virtualization server incommunication with at least one client computing device and providing ahosted application that includes user interface (UI) elements havingvertically or horizontally scrollable content that includes text andgraphics that are displayed at the at least one client computing device,and with the non-transitory computer readable medium having a pluralityof computer executable instructions for causing the at least one clientcomputing device to perform steps comprising: accessing the hostedapplication during one of the virtual machines sessions for receiving ahierarchical tree of the UI elements having the vertically orhorizontally scrollable content; displaying some of the UI elements fromthe hierarchical tree as at least a portion of the vertically orhorizontally scrollable content as local virtual UI elements, and basedupon the received hierarchical tree maintaining hidden the other UIelements as scrollable content; applying user input to scroll a portionof the displayed vertically or horizontally scrollable content; cachingthe hierarchical tree of scrollable content, and generating a localvirtual UI element graphics overlay and displaying the local virtual UIelements to which user input had been selected and scrolled and one ormore previously hidden UI elements as scrollable content correspondingto a predicted response to the user input; sending the user input tosaid virtualization server, and receiving updated UI element graphicsfrom the virtualization server that includes scrollable contentcorresponding to an actual response to the user input and replacing atleast a portion of the displayed local virtual UI element graphicsoverlay that includes at least a portion of the cached scrollablecontent with the received updated UI element graphics.